|The following information is from the Adventure Time comic book series. It may not be part of the same canon or continuity as the animated series.|
Adventure Time #39 is the thirty-ninth Adventure Time comic book. This issue features "Grocery Kingdom" as a back-up story, written by Kat Leyh.
The entire world of Ooo is not able to cook but Jake comes through and saves the day with his sandwiches. It's not over yet, though, as the witch is gonna summon her ultimate monster baddie.
The comic starts by saying that Finn and Jake fixed everything when a curse made everyone forget how to cook. Two candy people are eating, when Janice Bizzlethatcher breaks through the window and ruins their meal. She shouts that Arklothac is coming. Jake sternly asks her why she's messing with people's meals. Janice replies that a great chef will prepare a feast for Ooo. She says her original spell, which would have sent away the moon in exchange, would have brought him sooner. Because that failed, she used a different spell that takes longer. She cast another to make everyone forget how to make food so they would wait for Arklothac's cooking. Finn attempts to punch her, but Arklothac suddenly arrives, tearing through the sky.
Arklothac chops a mountain and takes a liking to the mineral composition. Janice gets his attention and tells him that she wants him to use the land to make a great meal for Ooo, which she loves so much. Arklothac says he will use every bit of it and serve it to his friends (their name is unpronouncable, but it concerns the local deities). He also says he has no idea who Janice is, who remarks this wasn't her plan. Arklothac then releases minions from his body to harvest the land, and Jake begins to fight them. Finn can't reach Arklothac with his sword lasers and refuses to fight the smaller enemies first. Jake asks Janice how to stop Arklothac. She suggests shutting down his temple and describes it. Knowing of that place, Jake leads Finn to it and they break some of the crystals, but it doesn't work. Finn draws a connection between the temple and the dungeon on the moon, and he thinks that a solution involving his sword is up there. However, Jake believes that Finn only wants to avoid getting hurt by the smaller foes and shoot lasers at Arklothac without getting hit. He leaves to fight the enemies himself, while Finn says that he's fighting smart.
Arklothac starts to boil the seas and turn them into soup rain. Finn races through the scalding soup to the moon portal. He claims it doesn't hurt, but it clearly does. Inside the space station, he tries to open the air lock, but the computer denies his orders. It says that "the classified zone is only for the Defender, who must remain flawless in health," and Finn is still injured. BMO, who has had enough of the computer, jumps out of Finn's backpack and hacks the system. With the air lock now open, Finn goes out and finds the Magnifier of the Defender, seeing that it's for the sword. He kisses his wounds, but it isn't enough to get his sword working again. Realizing his mistake, he tells BMO to hack into the moon-a-pault. Back on Ooo, Jake continues fighting Arklothac's minions. He stops when he sees something in the sky, which turns out to be Finn, having been launched from the moon. Sword in hand, Finn pierces through Arklothac and is caught by Jake.
Arklothac and his minions return to where they came from. Jake apologizes for not trusting Finn. Finn admits he was being weird and knew Jake would catch him. Jake says he could have thought Finn was a meteorite and wouldn't have caught that. This disturbs them both. They confront Janice and warn her not to do this again, though she says she'll keep trying to do nice things. Jake asks Finn if he can handle wielding the sword without being dumb about it. Finn says he can and that he just needs to be cool. Suddenly, the possessor monster reveals itself, telling Finn he wasn't killed and was inside the sword all along. Finn freaks out and throws the sword into the sea.
Jake is cooking in the kitchen, but panics when a jar of a certain ingredient is empty. His scream makes Finn rush in, and Jake says they need to go to the Grocery Kingdom. When they get there, Finn asks who the ruler is. Jake says there isn't one and that it's pure anarchy. As they enter, Finn gets a basket, but it is taken by someone wearing baskets. As the pair head through the battlefield of a store, Finn asks why they don't go to the candy mart in the Candy Kingdom. Jake answers that it only sells candy, not the rare stuff. They reach the aisle where the item is supposed to be, but it appears to be out of stock. Finn says there may be more in the back, so they fight their way there. However, they encounter a giant minotaur who grabs them both. He says he has what they're looking for and gives the ingredient to Jake. Finn asks how he knew, and he replies that he anticipates all with his third eye. He then tells them to flee the Grocery Kingdom. With the final ingredient, Jake finishes cooking the dish. He serves it to Finn and reveals that the last ingredient is pickled spider eyes. Finn is disgusted.